Egg Yolk Lecithin as a Dietary Supplement in Juvenile Silver Pompano, Trachinotus blochii: Effects on Growth and Health Parameters

Abstract

A 50-day feeding trial was conducted to determine the nutraceutical effect of a phospholipid, egg yolk lecithin (EYL) on juvenile silver pompano (Trachinotus blochii). The initial weight of the fish was (14.32 ± 0.12) g. The different dietary supplementation levels of EYL included 0% (EYL₀), 1% (EYL₁), 2% (EYL₂), 3% (EYL₃), and 4% (EYL₄). EYL supplementation has a positive impact on the growth and feed utilization of fish. The specific growth rate and weight gain percentage were significantly greater in the treatment group fed with 3% EYL. Feed utilization was observed to be highest in EYL₃ as feed efficiency ratio (FER) and protein efficiency ratio (PER) were higher in this treatment group when compared with all other treatment groups. The survival rate was observed to be 100% in all the treatment groups. Hemoglobin (Hb), mean corpuscular volume (MCV), packed cell volume (PCV), and red blood cells (RBC) values were greater for EYL₂, EYL₃ and EYL₄ whereas mean corpuscular hemoglobin concentration (MCHC) was unaffected by EYL supplementation. Nitro blue tetrazolium (NBT) activity was highest in the EYL₃ group. Dietary EYL supplementation significantly decreased blood glucose levels in the fish. Highest catalase (CAT) activity in the gills and liver was observed in the treatment group EYL₀. Superoxide dismutase (SOD) activity in the liver was unaffected and SOD activity in gills tended to decrease toward EYL₃ but increased in EYL₄. A significant reduction in the serum total protein concentration, serum globulin concentration, and an increase in serum albumin concentration and A:G ratio with respect to an increase in EYL indicate improved health. Serum triglycerides, creatinine, and uric acid were unaffected by EYL supplementation. However, HDL-cholesterol exhibited an increasing trend with an increasing EYL but decreased thereafter in EYL₄. These findings suggest a potential benefit of EYL inclusion above 1% up to 3% in the diets for promoting growth and health in juvenile silver pompano.